I've had the TV for two years. Began seeing 20-30 "hot" pixels" about a month ago. Randomly dispersed across the display. Initially it could be corrected by unplugging the TV. Eventually there were hundereds of hot pixels. If I leave the TV unpluged for about five days, problem goes away initially but slowly returns over three-four days. Someone has suggested that it could be a voltage problem with the TV but I don't know how to correct this. Any ideas??